Which media access control (MAC) protocols are specified for digital set-top boxes (STB)?

The correct choice, which includes ALOHA and time division multiple access (TDMA), is appropriate because these protocols are designed to manage how digital set-top boxes (STBs) access and utilize media in a communication network.

ALOHA is a pioneering protocol that allows devices to transmit whenever they have data to send, which is particularly suited for the sporadic data transmission needs of STBs. Although it is simple, it can lead to collisions that require retransmission, hence may not be as efficient under heavy load. However, its fundamental design fits well into the operation of set-top boxes that often send and receive information intermittently.

Time Division Multiple Access (TDMA) is a more structured approach that divides communication time into slots, where each device is assigned a specific time to transmit. This organization reduces the chance of collisions and increases the overall efficiency of the network, making it well-aligned with the needs of STBs that may require reliable, scheduled access to media streams.

This choice aligns well with the operation of digital set-top boxes, which often need to manage bandwidth amongst multiple streams and data requests efficiently.